Join Jo: How to Make Infusions for Use in Soapmaking (& Cosmetics!)

Are you ready for the next step on our plant colorant journey? I am so excited to teach you how to make infusions and see the results you achieve. Please share them with the rest of us in the comments section below!

Before we begin a quick word on cleanliness!

Regardless of what equipment or method of infusion you use, please ensure you use clean jars (recycled jars are great just make sure they are clean), clean utensils and clean hands. Make sure you have an accurate set of scales to 1oz and now let the fun begin!

How to Make Infusions with Plant/Botanical Material

Infusing can be done by two methods – cold or heat infusion. Cold infusion is my favorite, however, it’s up to you which way you prefer to infuse, and how quickly you would like to use the infused colorant may be the deciding factor.

A Collection of Jo’s Plant Infusions

Each infusion I make (cold or heat) starts out with 1 ounce of powdered plant colorant, or if I am using whole flowers or petals, one full jar (make a note of the weight before you add the oil). I record the weight of the whole flowers or petals so when I want to repeat the color, I know how I achieved it in the first place.

I never use fresh herbs for any of my infusions, although some people do with great success. I did try it once, and the smell and mold have definitely ensured I will never do that again!

If you don’t think you need this much infusion you can halve the above amounts, but I would encourage you to make the full jar. The infusion really does last quite a while, and you will have used it all long before the shelf life of the oil runs out.

How to Make Cold Infusions

This method is believed to be less harsh on the plants. I use it for both the healing properties (salves/balms) and the colorants that plants give.

Measure 1 ounce of powdered plant colorant, add to your jar, and fill the jar to the top with your chosen oil. Screw the lid on. If you are using whole flowers or petals, fill those to the top of the empty jar, cover them completely with your chosen oil and screw the lid on. You will need to stir and/or shake the jar to ensure all the colorant is mixed in.

Once the oil and the plant matter are mixed in the jar, I leave them on my kitchen bench, (or somewhere that I always see them – near the coffee or tea in my kitchen), for 7 days. Each day I turn and shake the jar twice a day, to ensure all the colorant touches the oil. After 7 days I move the jar to a shelf (low light area) and turn and shake the jar once a week for 6 weeks.

Over that time you will see the infusion start to change color. Some are quite instant (alkanet) and others will not even look like they have changed at all. Yellowdock in particular, gives a gorgeous strawberry pink in soap, yet will hardly change color in its infusion.

Beautiful Annatto (Bixa Orelana) Seed Infusion

Cold infusion takes about 6 – 8 weeks (I like mine to be 8+ weeks) before reaching a beautiful color. Not everyone chooses to place their infusion in a low light area, some prefer to leave their colorant on their kitchen window and allow some sun (heat) to enter the jar.

I don’t do this because once I make the soap, I try to avoid light to prevent oxidation of the plant matter that leads to the color fading. It makes more sense to me (and this is completely personal choice) to keep light away from the infusion and the soap to give the color the maximum chance of lasting.

However, what if you don’t have 6+ weeks and you are desperate to use a natural plant colorant that you just found at the local shop, or just arrived in a box of goodies in the mail? Heat infusion will be your best friend.

How to Make Heat Infusions

I use the same amounts of powdered colorant or whole flowers/petals as I do for cold infusion.

Some people use a heat sealable tea bag and place their powdered plant matter in the bag and then into the oil. The bag is used so they don’t have to strain the powder out of the oil at the end of the infusion. I use cheesecloth if I need to strain (you can use a coffee filter – takes forever!!!).

I have found that the powder settles to the bottom of the jar, and I can pour the colored oil straight off the top without having to strain.

An infusion with powdered botanicals that sunk to the bottom

I like to use an old crockpot for my heat infusion method. You can also use a large pot on the stove.

Once you have your power or whole flowers in the jar with the oil and the lid screwed on, place the jar into either the crockpot or the pan on the stove that you are going to use. Fill the crockpot or pan as high as you can with water and turn the heat on low or set the crockpot to low.

A set of infusions getting the crock pot treatment

Heat infusion takes 2 – 6 hours in the crockpot (low heat), or on the stove in a pan of water (again, low heat!) and the infused colorant can be used as soon as it is cool. I usually apply heat for 3 hours if I use this method, and I leave the jar until completely cooled in the water.

If you’re like me, you like to infuse different colorants at the same time, do yourself a favor and label the top of the jars. I do have those mystery jars sitting here and the only way to know what is in them to use them. I also date the jars and write the method of infusion on them.

Labeling the top of the jars is always a good idea!

Now you know how to infuse, next time I will show you how to use those infusions to achieve clear bright colors in your soapmaking. Are you ready?!

Jo Haslauer’s soap passions are plant colorants, botanicals & essential oils. She lives in Melbourne Australia, spends her time making soap, infusing herbs, running her business, and trying to demystify the world of plant colorants in cold process soap.

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Reader Interactions

What Folks Are Saying

Just a quick note – I do use a 16oz mason jar for my infusions. That means I would use 1oz of powdered plant colorant and then 15oz of oil (approximately depending on oil) to fill to the top of the jar. If I want to repeat a colour later on I can as I know the amounts that I have used.

Love this article! Thank you for sharing your expertise. My question is, when do those of us who do HP add the infusions to our creations? I’m particularly interested in the purples; Alkanet.
Thank you in advance!

Shari! My friend that I think is fantastic at HP has said you can add the Alkanet infusion at the beginning of the process as you would any other oil.

I would like to ask you a huge favour please, would you come back and share with us how you go with HP and an Alkanet infusion? I would love to know how purple your soap is after it has been subjected to the heat of HP.

I soap really cool with plant colorants and I am fairly sure your HP will be hotter than my CP ever would be so I would love to know what happens.

Thanks for your patience I really appreciate it whilst I sorted out an answer for you.

I’ve been extremely tardy in responding and want to thank you for finding out this information for me. I have yet to try it. I do have some Alkanet being infused at this time and hope to make some soap with it in the near future! I’ll let you know how it turns out!

Maria,
You can save it for the shelf life of the oil that you have infused the colour into 🙂 You don’t have to use it that day at all. If I heat infuse I let the infusion cool completely and usually don’t use it for a couple of days to let the colorant settle to the bottom. I don’t have to strain that way 🙂

Hey Jo! Thanks so much for sharing with us! ratanjot was not of this list and I want to use it for a lavender soap – what is your preferred method for that? I will be getting my infusions ready tonight!

Hi Paige,
Ratanjot I treat exactly the same way as Alkanet. Ratanjot is a little more grey in its colour of purple but gives my favourite purple and it is equally as good at holding its colour as Alkanet is.

Hi Connie!
Thank you for asking your question! Beetroot powder unfortunately is the same as fresh beetroot. At least for me. It is a gorgeous colour but infused or added to the lye or at trace that beautiful rich red will not last. It will turn brown 🙁

Spinach powder can be added at trace you will have some specks and it will give you a lovely green colour. As with all plant colorants fading will occur and it will eventually go towards the brown colourings as the plant matter oxidises with the light.

If you keep the spinach powder soap in the dark away from light whilst it is curing and then again when it is stored the colour will last a bit longer for you

Saffron infusions. Wold I still use 1 oz to 15 oz oil? I tried several threads in a table spoon of light color oil and saw no difference. However, in water I saw a vast improvement in color. Should I Lye with the saffron vs oil infusion? For a bold yellow?

Thank you so much for this series! I’m learning a lot. I just started my soaping journey, and my goal is to keep my soaps natural and not use any artificial colors or fragrances.
Can small amounts of the infused oils be used to color portions of the soap batter at trace to make swirled or layered patterns? Or would it work better to mix the powdered herb into a little oil and then mixed directly into the portioned out soap? I’ve seen tutorials where they do that with oxides but I’m not sure it would work the same with the herb powder.
Sorry for the long question!

Hi Sara,
Depending on the amount of oil you are going to require. If its a Tspn or even a Tbspn it wont make a lot of difference however if you require a lot more than that it will not work. I do use herb powders exactly the same as other people use oxides or micas – that definitely works. You will have specks in the swirl but there isn’t really a way around that if you add at trace

Hello Jo. Wonderful post. I have some dried hibiscus petals and I want to use them in soap. I can’t decide which is best, please help me out. Do I make hibiscus tea and use in place of water while mixing the lye or infuse the petals with olive oil or just add the hibiscus powder to oil base or soap at thin trace. Which of this methods will ensure the red from the hibiscus shines through or at least doesn’t turn the soap completely brown. Thanks.

I was taught (wow, a long time ago, I’m realizing!) to leave the lid on the jar unscrewed and tipped a bit to prevent condensation, as the air inside the jar will have some moisture. I take it this has not been a problem for you? (Thanks for the great article!)

Hi Jo.. I am just born in the CP world from India and found your articles of great help. Thanks a ton. Ppl like you make the earth beautiful place to live. I have infused various powders and herbs in oil an am about to make the soap. One comment of urs i want to be elaborated please

I would use the saffron in the lye water and that way you wont need as much!

Does this mean if you infuse in lye water u need less of the herb ? but i find then we are not sure of the color we will get. i am experimenting. Hope ppl in india are receptive to the new idea of natural soaps….
Can you please tell me about the process of making swirls with zinc oxide on your soaps. They look adorable. Thanks for the help.

Thank you for your comments. Saffron is very strong so you will only need a small amount to achieve a bright color. The heat from the lye solution will draw out the yellow more and you will need less to achieve the same depth of color because of the high heat than if you were to add the saffron to your batter at trace. I hope that helps to explain why I would use it in the lye water

I dont know how to explain my swirls other than I just put the chop stick in and dont take it out until I have finished all the surface.

[…] informative series of posts over at Modern Soapmaking – (1) Coloring Soap Naturally, (2) How to Make Infusion for Soapmaking, (3) How to Use Plant Infusions in Soap Making & (4) Using Natural Colorants in Your Lye […]

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